Sewing machine



lMarh 2 1926.

J. SCHREIBER SEWING MACHINE Original Filed May 2l, 1921 QN h. mw Nw, m f W\ m l. m.. H ...UTL'H NM.

Patented Mar. 2, 1926.

UNITED STATES JOHN SCHREIBER, OF ST. LOUIS, MISSOURI.

SEWING MACHINE.

Original application filed May 21, 1921, Serial No. 471,314. Patent No. 1,440,556, dated January 2, 1923. lDivided and this application filed December 18, 1922. Serial No. 607,531.

To all whom z' hwy-concern.'

Be it known that l, JOHN Sonnninn, a citizen of the `United States, residing at the city of St. Louis and State of Missouri, have invented a new and useful Sewing Machine, of which the following is a specification.

This invention relates to sewing machines and has special reference to means for tensioning a thread passing to the stitching mechanism.

An object of the invention is to provide a device for tensioning a thread passing to the stitching mechanism under control of the same operatingdevice that operates the stitching mechanism, so that perfect accord and timing of the operation of the tensioning device and stitching` mechanism are maintained. v

Another object of the invention .is to provide a tensioning device of the specifically novel and useful constructionvherein shown and described. v 1

Another object of the invention is to provide an improved `tensioning device specially designed and adapted for use in the sewing machine constituting the subject-matter of my application Serial No. 471,314, filed May 21, 1921, patented January 2, 1923, No. 1,440,556, from which application the present case is divided.

In the drawings Fig. 1 is a view with parts in section and parts in elevation showing the present invention embodied in a machine of the type mentioned. f

Fig. 2 is an enlarged sectional view of the tensioning device. p

Fig. 3 is a detailed view showing the cam bar for operating the tensioning device and the `lever for taking up the slack of the thread between the tensioning device and the stitch forming mechanism of the machine.

The cam housing 1 supports the front head frame 2 at the forward end of which a work supporting 'plate 3 is mounted. The needle 4 is operatively supported within the frame 2 for operation Vby mechanism (not shown) driven by a shaft 5 in the cam housing 1. The thread 6 passing to the needle 4 is controlled and tensioned by the present invention.

The tensioning device includes a stem 7 mounted for reciprocating movements` in a boss 8 on the. top of the front head frame, the lowerv end of' said stem Aextending through and below the top wall of the front head frame. The upper end of the stem 7 projects through the top wall of the cap 9 that is attached to the face of the boss 8 by screws 10 which permit removal of the cap and the stem 7 as well as the associated parts. r:The stem 7 has a circumferential flange 11 rigid thereon. An expansion spring 12 encircles the stem 7 having its lower end bearing upon the flange 11 and its upper `end pressing against the upper wall of the cap 9, the tendency of said spring being exerted to actuate the rstem 7 down wardly. A washer 13 is loosely mounted ,on the stem 7 below the iiange 11 and an ein pansion spring 14 around the stem 7 has its upper end pressing against the washer 13 and its lower end bearing upon the lower wall of a recess in the boss 8. u

At each side of the cap 9' a slot 15 is formed. The lower side of the flange 11 is in line with said slots. The thread 6 passes through the .slot 15 on one side of the cap, is looped around the stem 7 between the flange 11 and the washer 13, and is passed out throughvthe same'slot 15 that it enters,

the slot on the opposite sideibei'ng provided for convenience in initially passing the thread through the device r)This tensioningl device functions to tension and release the thread, maintaining suiiicient pressure thereon to prevent overrunning of the thread whenvthe thread is carried forwardly by the operation of the needle 4.v At the proper time the thread is locked against forward movement, permitting the stitching mecha-- nism,of which the needle 4 forms a part, to tighten the thread.` This operation of the tensioning device is effect-ed by means of a cam bar 16 mounted for sliding movements in a channel 17 formed within the upper wall of the cam housingl. The cam bar 16 extends to a point near the rear end of the cam housing and supports a roller 18 operating within'a cam slot 1 9` formedA in a cam cylinder 2O attached to the shaft 5.

The forward end of the cam bar 16 has an inclinedy cam slot 21, the lower wall of which extends obliquely upwardly land rea-rwardly and upon which the lower end of the stem 7 rests. The lower end of the stem 7 has a flattened portion 22 to enter the slot 21 and prevent the stem from turning.V

The stem 7 is provided with a manual-re-y leasing devlce inthe form of a cam lever 23 having a cam device 24 operating on the top wall of the cam 9. The lever 23v is pivoted to the end of the stem 7 by a screw 25. Then the lever 23 is in a vertical posi-tion, as shown in Fig. 1, the stem 7 is upheld thereby and is prevented from being pressed downwardly by the spring 12 which would otherwise occur when the cam bar 16 moves toward the right, as shown in 1. In this position the washer 13 is yieldingly supported by the spring 14 so that the pressure of the washer 13 toward the flange 11 is diminished, permitting the thread to be drawn with only sufiicienttensi'on to prevent it from overrunning. This position of the device is termed the released position and is assumed only when it is desired to reduce the tension and restraint on the thread 6, as when the thread is being drawn forward by hand for threading the stitching mechanism. y

When the lever 23 is depresed the stem 7 is free to move in its mounting and when the stem is in its lowest position the washer 13 rests upon the upper wall of the boss 8. In this position the spring 12 has sufficient tension to cause the flange 11 and the washer 13 to bind the thread between them and prevent it from moving forwardly. This ad'- justment of the device iseffected when the cam bar' 16 is at the extreme rear position, that is at the extreme' right as seen in Fig. 1, which is at the time that the stitch is being drawn into the work. Subsequently, and at the proper time, the, cam bar 16' is moved forwardly toward the left, as seen in Fig. 1, raising the stem 7 iii-opposition to the spring 12 so that the washer 13 will be yieldingly supported by the spring 14. The

tension of the spring 1A is such that there is sufficient play between the washer 13 and the flange 11 to permit thel thread 6 toA be drawn forwardly by the stitching mechanism and at the same time to prevent the overrunning of the thread. A From the tension device the thread is passed under a guide roller 26 on a stationary support 27. An arm 28 extends out wardly and acrossthe roller groove to prevent they thread from slipping. out of the groove and the roller. From the roller 26 the thread passes over a second roller 29 supported at the extreme of a rocker arm 3() that constitutesimeans for drawing the stitch into the material after the stitch has been formed and when the needle 4 is raised, The roller 29 is provided with an arm 31 for preventing theV thread from working ofi the roller. From the roller 29 the thread 6 passes downwardly to the needle 4.

The lever 30v is pivoted on the upper end of a lever 32 by a pivot 33 which serves as a pivotal connection for the forward end of a link 34, the rear end of which is connected to the cam bar 16 by pin fin slot connection 35. A springk 36 held around the hubs of the levers 30l and 32 engages the lever 30 and tends to raise the forward ends of said lever in opposition to the pressure imparted thereto by the thread 6 passing over the roller 29. An adjustable abutment 37, in the form of a screw passing through a projection on the depending end of the Iever 30, is adapted to contact with the lever 32 to limit downward movement of the lever 30 relative to said lever 32. A spring 38 connects an extension of the lever 32v below the pivot 39 of said lever with a stationary part of the machine and serves to operate the upper end of the lever 32 in a forward direction. Forward movement of the upper ,end of the lever 32 is limited by an abut ment 40. A screw 41 is adjustably supported by the lever 32 and contacts with the` abutment 40 to limit forward movement of said lever, and constitutes means for varying extent offmovement of said lever 32.

- From the foregoing it will be seen that my invention is a perfect embodiment for accomplishing its intended objects and pnrposes and is specially designed and adapted for use in a machine of the type mentioned, although its utilitv is not restricted to such a machine. A

The construction and arrangement may be varied without departure from the principle of the invention and I donot restrict myself unessentially, but what I claim and desire tor secure by Letters Patent is 1. In a sewing machine having stitch forming mechanism, the combination of a stem supported for axial movements, a flange rigid on said stem, a spring encircling the ste-m and bearing against said flange to actuate the stem in one direction, a washer loose on said stem on the opposite side of said flange from said spring adapted to press against the thread passing between said washer and said flange, and a spring encircling the stem for pressingl the-washer toward said flange.

2. In a sewing machine having stitch forming mechanism, the combination of a stem supported for axial movements, a flange rigid on said stem, a spring encircling the stem and bearing against said flange to actuate the stem in one direction, a washer loose on said sten-1 on the opposite side of said flange from said spring adapted to press against the thread passing between said washer and'said flange, a spring encircling the stem for pressing the washer toward said flange, and a cam device for moving said stem axially i-nopposition to the firstnamed spring. v

3. In a sewing machine having stitch forming mechanism, the combination of a housing having an internal shoulder and having openings through the walls of the housing above said shoulder, a stem ex,-

Lll)

tending through the housing for axial movements, a flange rigid on said stem and having its lower surface in line with said openings, a spring encircling the stem and bearing against said flange to actuate the stem in one direction, a washer loose onl the stem on the opposite side of said flange 'from said spring and arranged to seat upon said shoulder when said stem is in itslower position, and a spring encircling the stem below said washer for pressing the washer toward said flange.

4. In a sewing machine having stitch forming mechanism, the combination of a housing having an internal shoulder Vand having openings through the walls. of the housing above said shoulder, a stem extend ing through the housing for axial movements, a flange rigid on said stem and having its lower surface in line with said openings, a spring encircling the stem and bearing against said flange to actuate the stem in one direction, a washer loose on the stem on the opposite side of said flange from said spring and arranged to seat upon said shoulder when said stem is in its lower position, a spring encircling the stem below said washer for pressing the washer toward said flange, and a device in connection `with the outer end of said stem for raising the stem in opposition to said first named spring.

5. In a sewing machine having Astitch forming mechanism, the combination of a stem supported for axial movements, a flange rigid on said stem and having a thread engaging side, a spring encircling the stem and bearing against said flange to actuate the stem in one direction, a cam for moving the stem in opposition to said spring, a washer loose on said stem and ar ranged to press the thread against said flange, and an additional spring actuating said washer toward said flange to hold the thread between said flange and washer during operation of said stem by said cam.

6. In a sewing machine having stitch forming mechanism, the combination of a stem supported for Yaxial movements, av thread lock device on said stem, a cam having a cam slot therein in which said stem extends and by which said stem is held from turning, and means'for operating said cam to actuate said stem Iin one direction.

7. In a sewing machine,.a stem supported for axial movements, a flange rigid on said stein, a washer loose on said stem, a spring for pressing the washer towardk the flange,

a cam bar having a slot into which said stem extends and by which said stem is held from turning, and means for operating said caml bar to move said stem in one direction.

8. In a sewing machine, a support, a cap attached to vsaid support, a stem supported for axial movements through said. support and said cap, a flange rigidon said stem, a washer loose on said stem, springs encircling said stem and bearing against said support and cap respectively and pressing said washer and said flange toward each other, a lever in connection with said `stem operative to move said stem in a direction to compress one of said springs and to permit ex ansion of the other spring, and means for preventing said stem from turning.

9. In a sewing. machine, a stem supported for axial movements,a flange rigid on said stem, a washer loose on saidstem, a spring for pressing the washer toward the flange, a cam bar having a slot into which said stem extends and by which said stem is held from turning, means'for operating said cam bar to move said stem` in one direction, and a spring for moving said stem in the opposite direction.

JOHN v scnannsna@ 

